The areas under investigation are: pyrethroids, chlorinated hydrocarbons, compounds inhibiting or uncoupling oxidative phosphorylation, organophosphorus and methylcarbamate insecticide chemicals, and other toxicants and chemicals potentially useful in pest insect control. Studies on pyrethroids include radiosynthesis, metabolism, photodecomposition and mode of action with emphasis on newer, selectively toxic synthetic compounds. While some investigations are continuing on tetrachlorodibenzo-p-dioxin, photosensitizers to accelerate residue dissipation, and photoisomers of methano-bridged cyclodienes, the major program on chlorinated hydrocarbons concerns the composition, identity of components, metabolism and environmental fate of toxaphene. The emphasis on compounds disrupting respiratory metabolism will shift from rotenone and uncouplers of oxidative phsphorylation to other types of inhibitors, particularly organotin compounds. Studies on organophosphorus and methylcarbamate compounds will include the metabolism and photoalteration of Delnav and selected methylcarbamates, the chemical and biological oxidation of thionophosphorus compounds, and the mechanisms of side effects including teratogenesis and delayed demyelination and neurotoxicity using cyclic phosphorus compounds to induce these lesions. Other subjects to be investigated include: the metabolism in mammals and mechanism of herbicidal action of a large number of thiolcarbamates; the metabolism in mammals and insects and the environmental fate of insect juvenile hormone analogs.